pmdazswap(1) — Linux manual page


PMDAZSWAP(1)             General Commands Manual            PMDAZSWAP(1)

NAME         top

       pmdazswap - zswap (compressed swap) PMDA

DESCRIPTION         top

       pmdazswap is a Performance Metrics Domain Agent (PMDA) which
       exports metric values about compressed swap operation, as tracked
       by the zswap Linux kernel module.

       Zswap is a lightweight compressed cache for swap pages.  It takes
       pages that are in the process of being swapped out and attempts
       to compress them into a dynamically allocated RAM-based memory
       pool.  Zswap trades CPU cycles for potentially reduced swap I/O.
       This tradeoff can also result in a performance improvement if
       reads from the compressed cache are faster than reads from a swap

       This PMDA exports metrics about pool size, number of pages
       stored, and various counters for the reasons pages are rejected.

INSTALLATION         top

       Install the zswap PMDA by using the Install script as root:

           # cd $PCP_PMDAS_DIR/zswap
           # ./Install

       To uninstall, do the following as root:

           # cd $PCP_PMDAS_DIR/zswap
           # ./Remove

       pmdazswap is launched by pmcd(1) and should never be executed
       directly. The Install and Remove scripts notify pmcd(1) when the
       agent is installed or removed.

FILES         top

           installation script for the pmdazswap agent

           undo installation script for the pmdazswap agent

           default log file for error messages from pmdazswap


       Environment variables with the prefix PCP_ are used to
       parameterize the file and directory names used by PCP. On each
       installation, the file /etc/pcp.conf contains the local values
       for these variables.  The $PCP_CONF variable may be used to
       specify an alternative configuration file, as described in

SEE ALSO         top

       PCPIntro(1) and pmcd(1).

COLOPHON         top

       This page is part of the PCP (Performance Co-Pilot) project.
       Information about the project can be found at 
       ⟨⟩.  If you have a bug report for this manual
       page, send it to  This page was obtained from the
       project's upstream Git repository
       ⟨⟩ on 2023-12-22.
       (At that time, the date of the most recent commit that was found
       in the repository was 2023-12-16.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to

Performance Co-Pilot               PCP                      PMDAZSWAP(1)